Photochemical transformations of small ring compounds. 95. The problem of regioselectivity in the photochemical ring-opening reaction of 3-phenyl- and 3-vinyl-substituted cyclopropenes to indenes and 1,3-cyclopentadienes

Padwa, Albert; Blacklock, Thomas J.; Getman, Daniel P.; Hatanaka, Naoto; Loza, Roman

doi:10.1021/jo00402a002

Cited by 56 publications

(31 citation statements)

References 35 publications

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“…[6]) indicate that the origins of allene 6, alkyne 7, and 1,3-dienes 8-10 can all be rationalized as due predominantly to formal [1,2]-or [1,4]-H migrations in the two possible vinylcarbene intermediates (18 and 19; see eq. I l l ] ) , as expected (3,15).…”

Section: Discussionmentioning

confidence: 99%

“…that typical of arylcyclopropenes. These compounds afford substantial amounts of allene and alkyne products in addition While the photochemistry of arylcyclopropenes has thus been to the 1,3-dienes and other products that are characteristic of , extensively investigated (1)(2)(3)(4)(5)(6)(7)(8), there have been few reported vinylcarbene intermediates. The photochemistry of compounds ' studies of simple alkyl-substituted derivatives in solution and supplements the elegant studies of Steinmetz er (I6, 19), probably because the parent chromo~hOre is devoid Of (16)(17)(18) and Johnson and co-workers (19)(20)(21) on the photoabsorption above 210 nm and hence requires the use of ,-hemistry of allene derivatives.…”

Section: + A+a+m+mentioning

confidence: 99%

“…[6]. Products 14 and 15 were identified by coinjection of the photolysate with authentic samples on two different vpc columns.…”

Section: 33-trimethylcyclopropenementioning

confidence: 99%

“…The yields listed in eqs. [5] and [6] for the photolyses (193 nm) of 3 and 4 in pentane represent the averages of the determinations at several conversions below 5%.…”

Section: 35-trimethyl-24-hexadiene (15)mentioning

confidence: 99%

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The far-ultraviolet photochemistry of alkylcyclopropenes in solution

Fahie¹,

Leigh²

1989

Can. J. Chem.

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This paper is dedicated to Professor Ronald J . Gillespie on the occasion of his 65th birthday BRIAN J. FAHIE and WILL~AM J. LEIGH. Can. J. Chem. 67, 1859Chem. 67, (1989. The photochemistry of 1,3,3-trimethylcyclopropene and 1-tert-butyl-3,3-dimethylcyclopropene has been investigated in hydrocarbon, methanol, and 1-hexene solution with far-ultraviolet (185-228 nm) light. Direct photolysis of the two compounds affords allene, alkyne, and 1,3-diene derivatives, formally as a result of initial bond cleavage to yield vinylcarbene intermediates. Products derived from cleavage of the most substituted (Cl-C3) cyclopropene bond account for 60-80% of the observed mixture in each case. Results from the photolysis of 1 ,3,3-trimethylcyclopropene-1-13C suggest a second pathway for formation of alkyne products in cyclopropene photochemistry, which occurs in competition with (or by exclusion of) the vinylcarbene

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Section: Discussionmentioning

confidence: 99%

Section: + A+a+m+mentioning

confidence: 99%

“…[6]. Products 14 and 15 were identified by coinjection of the photolysate with authentic samples on two different vpc columns.…”

Section: 33-trimethylcyclopropenementioning

confidence: 99%

“…The yields listed in eqs. [5] and [6] for the photolyses (193 nm) of 3 and 4 in pentane represent the averages of the determinations at several conversions below 5%.…”

Section: 35-trimethyl-24-hexadiene (15)mentioning

confidence: 99%

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The far-ultraviolet photochemistry of alkylcyclopropenes in solution

Fahie¹,

Leigh²

1989

Can. J. Chem.

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“…Some examples chemistry of the vinyl methylenes formed (1)(2)(3). are summarized in reactions [I] to [4].…”

Section: Introductionmentioning

confidence: 99%

The thermal chemistry of vinyldiazo compounds as a method for the generation of vinylmethylenes

Pincock¹,

Murray²

1979

Can. J. Chem.

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. Can. J. Chem. 57,1403Chem. 57, (1979. The thermal chemistry of a series of substituted 1-aryl-3-methyl-2-phenyl-1-diazobut-2-enes has been examined. These vinyldiazo compounds react in two parallel pathways: cyclization to a 3-aryl-5,5-dimethyl-4-phenyl-5H-pyrazole or loss of nitrogen and cyclization to a l-aryl-2-phenyl-3,3-dimethylcyclopropene presumably by a vinylmethylene intermediate. The kinetics of these processes reveal quite different substituent effects. The relation of these results to the stability of the vinylmethylene produced and to the singlet photochemistry of cyclopropene derivatives is discussed. JAMES A. PINCOCK et KIM P. MURRAY. Can. J. Chem. 57,1403Chem. 57, (1979. On a ktudie la thermochimie d'une skrie d'aryl-1 mkthyl-3 phenyl-2 diazo-1 butbnes-2 substituks. Ces composks vinyldiazo rkagissent par deux voies paralltles: une cyclisation conduisant a l'aryl-3 dimkthyl-5,5 phknyl-4 5H-pyrazole ou une perte d'azote et une cyclisation en aryl-1 phknyl-2 dimkthyl-3,3 cycloproptne probablement par un intermkdiaire vinylmkthylbne. Des ktudes cinetiques de ces processus rkvtlent des effets de substituants importants. On discute de la relation qui existe entre ces rksultats et la stabilite du vinylmkthylene qui est produit ainsi que la photochimie singulet des dkrivks du cycloproptne.[Traduit par le journal] IntroductionHowever, recent results for cases with unsymmetrical The photochemical reactivity of the singlet excited substitution on the double bond (1, 2, 4, 5) have state of cyclopropene derivatives has generally been led to considerable speculation as to the effect of explained in terms of o bond cleavage and the these substituents on ring cleavage. Some examples chemistry of the vinyl methylenes formed (1-3). are summarized in reactions [I] to [4].

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The Vinylcyclopropane–CyclopenteneRearrangement

1985

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The vinylcyclopropane‐cyclopentene isomerization was discovered in 1959. After the mechanism was studied in detail, this rearrangement was incorporated into many useful synthetic schemes. Various heterocyclic permutations of the vinylcyclopropane system have also been investigated, yielding several synthetic methods based on the rearrangements of cyclopropyl ketones and cyclopropyl imines to dihydrofurans and dihydropyrroles, respectively. This chapter is concerned only with the rearrangements of vinylcyclopropanes to cyclopentenes. Excluded are Cope rearrangements of divinylcyclopropanes and rearrangements of cyclopropyl compounds not leading to cyclopentenes. The isomerization of 2,2‐dichlorovinylcyclopropane was described in 1959. The rearrangement of the parent hydrocarbon was reported independently by two laboratories a year later. Although no prior mention of this rearrangement exists in the literature, it appears likely that it occured unobserved as early as 1922 during the preparation of vinylcyclopropane by drastic methods. The presence of cyclopentene in the reaction mixtures resulting from the Hofmann elimination of a β‐cyclopropylethylammonium salt is a likely possibility, considering the low temperature at which vinylcyclopropane rearranges. The detection and identification of reaction products by refractive indices only may have prevented recognition of the isomerization at that time. During the decade following the discovery of the rearrangement, virtually every simple vinylcyclopropane was studied in an attempt to settle the question of biradical versus concerted mechanism. Later there was intense activity in the applications of this rearrangement and many of its analogs to organic synthesis. Studies have also emphasized transition‐metal‐catalyzed rearrangements of vinylcyclopropanes.

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Photochemical transformations of small ring compounds. 95. The problem of regioselectivity in the photochemical ring-opening reaction of 3-phenyl- and 3-vinyl-substituted cyclopropenes to indenes and 1,3-cyclopentadienes

Cited by 56 publications

References 35 publications

The far-ultraviolet photochemistry of alkylcyclopropenes in solution

The far-ultraviolet photochemistry of alkylcyclopropenes in solution

The thermal chemistry of vinyldiazo compounds as a method for the generation of vinylmethylenes

The Vinylcyclopropane–CyclopenteneRearrangement

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